EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, 30-31 March The potential of MTG-IRS to detect high pollution events at urban and regional.

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Presentation on theme: "EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, 30-31 March The potential of MTG-IRS to detect high pollution events at urban and regional."— Presentation transcript:

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March The potential of MTG-IRS to detect high pollution events at urban and regional scales Aim The study investigates the capability of IRS onboard MTG to detect enhanced levels of carbon monoxide (CO) and ozone (O 3 ) at local and regional scales, in particular over Europe. People involved Cathy Clerbaux, Anne Boynard (SA/IPSL- CNRS, Paris) Pierre Coheur, Oliver Scharf (ULB, Brussels) Some slides extracted from a former study

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March >> Detection of pollution peaks with IR instruments -Controlled pollutants are O 3, CO, NO 2, SO 2, PM; Ozone : peaks in the afternoon. Alert levels exceeded several days per year. Current prediction scores around 50%. CO : Alert levels exceeded only when big fire events occur. - All controlled pollutants but ozone are continuously decreasing above Europe; - O 3 and CO (and SO 2 -volcano) are measured by TIR; - Thermal contrast is high during the day and during the spring/summer, over land. Ozone /IASI: Profiles retrievable but low sensitivity near the ground. CO /MOPITT and IASI: Cities can be seen if favorable thermal contrast. Fires are easy to be detected because it is a large signal.

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March Vertical sensitivity from the ground to about 40 km but low sensitivity to the surface DOFS around 3.5  single information in the troposphere Errors range from 20 to 40 % on individual levels above 2 km while errors in the PBL are close to the a priori variability. Error on the tropospheric column is around 15 % Improving noise and/or spectral resolution (IRS-MTG vs. Sentinel 4) improves retrieval performances in the lower troposphere. Impact of thermal contrast (  T=T ground -T ): Impact is in the lower troposphere. The error on the tropospheric column reaches ~ 10 % for positive values of  T Despite a priori far from the target: Significant improvement with respect to a priori over the entire troposphere. Errors around 12 % on the tropospheric column for vanishing thermal constrast decrease to 5 % for  T values of 5 K or larger. Similarly PBL errors decrease to 50 % for  T values of 5 K or larger. Diurnal variations are hardly reproduced for the case analyzed here (retrieval errors being of the order of the diurnal variability). Sentinel 4 goal closest to the truth in PBL. Conclusions of Part II: Sensitivity analyses - retrieval experiments B. Retrieval experiments A. Sensitivity analyses Ozone retrievals from IRS-MTG

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March General conclusions 1)CO and O 3 pollution events in Europe are occurring in summer + daytime (O3) 2) Thermal contrast is higher during day and summer, over land 3) Current instruments show an improved sensitivity towards the surface when there is a thermal contrast 4) IRS has a limited sensitivity for the PBL but is able to provide more measurements including in the afternoon 5) IRS-S4 provides improved measurements in terms of accuracy and vertical information/sensitivity

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March General conclusions Will IRS/MTG be able to detect pollution events ? Yes, because extreme events generally occur over land/during day when thermal contrast (and hence instrumental sensitivity) is high Is IRS/MTG the instrument we would like to have to perform TIR chemistry measurement from a geo? No, because of limited vertical sensitivity and accuracy, in particular in the boundary layer Is IRS/MTG able to detect the diurnal variability for O3 et CO? Probably not, because of limited sensitivity and low diurnal variability Will the complementarity with UVN-S4 will help to improve O3 ? Yes, because of different vertical sensitivity a combined retrieval will provide an improved product

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EUMETSAT MTG Missions for AQ Monitoring ACC#5, CSA, Montreal, March Number of exceedance days of the threshold value for the information to the public CO O3O3 Years 2003, 2004 et 2005 (49 days over limit) All pollutants + all regions Ozone Paris Ozone Suburb Dioxyde d'azote Paris Event forecasted63%45%68%33% Un-detected event29%26%31%28% False alarm37%55%29%67% Courstesy to Air Parif - Introduction: Air quality